TAMPA — Dog trainers in Hillsborough County must obtain a license and agree to training plans with pet owners before beginning instruction, county commissioners decided on Wednesday.

The new ordinance, called Truth in Training, is the first of its kinds in the country, county officials have said.

The 5-2 vote came amid fierce opposition from many local dog trainers, many of whom warned the new regulations would inhibit their small businesses. They also said it would discourage certain training methods, for fear of litigation.